The invention relates to apparatus for preheating charges of raw material with hot gases prior to application of the charge to an electric furnace.
In the manufacture of ferroalloys and the like using electric furnaces, the iron to be alloyed is introduced into the furnace together with a charge of an alloying material in raw form, which has been pre-heated. The preheating operation is accomplished via the combustion of gases resulting from the operations in the electric furnace.
A separate rotary or shaft kiln is generally provided around the electric furnace for holding the charge and receiving the hot combustion gases for preheating. Additionally, an additional furnace is often provided in such systems for effecting the combustion of such gases prior to their introduction into the furnace-surrounding kiln.
Such systems have the disadvantage of being bulky, space-consuming, complicated and expensive, as well as requiring additional facilities for transporting the preheated charge from the kiln into the electric furnace. Additionally, the auxiliary kilns are inefficient and generate large amounts of dust.